Time-travel flick Looper is set in 2044 — a time when America is verging on dystopia and assassins called “loopers” are hired by criminal syndicates to kill enemies sent back from the future. Making that world seem authentic was one of the challenges of filming Looper, and keeping it real meant that it didn’t look too perfect — vehicles still break down and even three decades in the future cellular networks still don’t have full coverage out in the sticks.

“We were trying to create a really grounded near-future dystopia,” Looper director Rian Johnson tells Wired in the video interview above. “But even the futuristic stuff that we’ve built into it we tried to knock down a little. Like, there’s hover bikes, but they kind of don’t work that well. They’re not actually that good. And the phones still don’t get reception.”

The other thing that was challenging to keep authentic? Making Joseph Gordon-Levitt, who plays a looper named Joe, look like a younger version of Bruce Willis, who plays an older Joe sent back from the future to get whacked by his younger self. Some of it was accomplished thanks to clever makeup and prosthetics — “putting on another actor’s face,” as Johnson says — but the rest was The Dark Knight Rises actor meticulously studying his muse.

“I did work on it for a long time, actually,” says Gordon-Levitt, who previously worked with Johnson on 2005’s Brick. “I’d watch his movies, I’d rip the audio off of his movies and put them on the iPod so I could listen on repeat. But the most useful thing was just spending time with him and hanging out with him and having dinner and letting it seep in that way.”

Creating the future and characters to fill it for film is one thing. But if given the chance, would the director or his star actually time travel? Actually, yes. But only forward, never back in time, where it’s too easy to alter the course of history forever.

“I’m very happy where I am right now, I don’t want to muck anything up,” Johnson says. “Let’s see what the iPhone 12 is … You don’t want to go too far because then you end up on a charred piece of Earth spinning through space all alone.”